Paving machine



Feb. 23, 1954 K. E. MccoNNAUGHAY PAVING MACHINE 2 Sheets-Sheet l FiledMarch 14, 1946 Feb. 23, 1954 K. E. MccoNNAuGl-IAY 2,669,915

PAVING MACHINE Filed March 14, 1946 2 Sheets-Sheet 2 Patented Feb. 23,1954 UNITED STATES PATENT oFFIcE 8 Claims.

My invention relates to a machine for mixing and spreading pavingcompositions. It is an object of my invention to produce a machine whichcan be moved over a surface to be paved and which, while being so moved,will mix and spread a paving composition. A further object of myinvention is to produce a machine in which the paving composition willbe spread and leveled within a short period of time following itsmixing. Another object of my invention is to produce a machine whichwill `quickly and readily produce a paving-material slab of varyingthickness. Still another object of my invention is to provide a machinewhich will lay a slab of paving material having a composition whichvaries transversely of the slab.

In carrying out my invention in its preferred form I employ a Vehicleadapted to be driven or drawn over the surface to be paved. Such vehiclemay be supported in any convenient manner, as on wheels or on acombination of wheels and skids. Carried by the vehicle there is atransversely extending bin adapted to receive the aggregate which is tobe incorporated in the paving composition. Also carried by the vehicleis a means providing a mixing compartment into which aggregate from thebin is fed at regulated rate desirably in the form of a thin sheethaving a width approximately equal to that of the nished slab. Aggregateentering the mixing compartment is sprayed with a binder and is thensubjected to the action of one or more longitudinally rotating mixingelements having fingers which engage the material and throw it violentlyupwardly against the upper wall of the mixing compartment. Such mixingelements rotate on axes extending transversely of the vehicle andconsequently do not tend to displace any of the aggregate particles fromthe respective planes they occupy in entering the mixing compartment. Anadjustable gate regulates discharge of mixed material from the mixingcompartment, while a blade located in rear of the mixing compartment andmounted for vertical adjustment distributes and levels the mixedmaterial. Individual-gates extending in a series transversely of thevehicle `permit regulation of the amount of aggregate fed from the binat various points, and consequently control the transverse distributionof the mixed material discharged from the mixing compartment. The binderis desirably sprayed upon the aggregate through a spray bar embodying aseries of individually controllable nozzles extending transversely ofthe vehicle, whereby the amount of binder may likewise be varied.

The machine can be adapted for the laying of a composite pavement byproviding it with a second bin, feed-regulating gates, and spray bar.For example, the second bin might contain Portland cement, and the twospray bars might be respectively supplied with water and a bituminousbinder. By proper adjustment of the gates respectively associated withthe two hoppers and by proper regulation of the independentlycontrollable valves of the spray bars, the machine may be used to lay aconcrete pavement embodying a portion containing a suilicient quantityof bitumen to enable it to function as an expansion joint; or abituminous slab might be layed simultaneously with a concrete edge orshoulder.

The accompanying drawing illustrates my invention. Fig. 1 is a plan viewof the complete machine with portions thereof broken away; Fig. 2 is aside elevation of the machine, likewise with portions thereof brokenaway; Fig. 3 is a fragmental longitudinal vertical section illustratingdetails of construction; Fig. 4 is a fragmental section on the line 4-4of Fig. 3; and Fig. 5 is a view similar to Fig. 3 illustrating amodified form of construction.

The machine illustrated in the drawings comprises a vertical framesupported in part on wheels I0 and provided with hitches II by which thevehicle is adapted for connection to a truck or other means suitable fordrawing it over the surface to be paved.Y Extending transversely acrossthe front end of the vehicle is an aggregate hopper or bin I2 desirablyprovided with a grille I3 and below such grille with a distributingscrew I4 adapted when rotated to distribute the aggregate outwardlytoward the ends of the bin. As shown, the bin is provided with anintermediate divider I5, but such divider may be omitted or additionaldividers may be employed as desired. The arrangement of the hopper I2and hitch II is desirably such that the body of a dump truck connectedto the hitch II may discharge into the hopper.

Associated with the hopper is a feeder I1, here shown as of the belttype, which discharges rearwardly into a mixing compartment I 8 havingend walls I9, a top wall 20, and bottom wall 2l. In the specificconstruction illustrated, the bottom wall ZI serves as a skid engagingthe road surface and cooperating with the wheels I0 to support thevehicle. It is to be understood, however, that other means may be usedin co-operation with the wheels Il) to support the vehicle and that insuch a case the bottom wall 2| of the mixing compartment may be omittedAand the material discharged from the feeder l1 directly on to thesurface to be paved.

Extending transversely of the vehicle within the mixing compartment I8are a pair of parallel, horizontal shafts each provided with a pluralityof axially extending rows of mixing teeth 25. Desirably, the teeth 26are curved in such a direction as will aid them in lifting the aggregatewhich is discharged into the mixing compartment. As shown, the twoshafts 25 rotate in opposite directions, the front one rotating in adirection such that the teeth 26, when below it, will be movedrearwardly and the rear one rotating in the reverse direction, the twoshafts being so angularly related that the teeth of one do not interferewith the teeth yof the other. In this particular shaft-arrangement,which is not essential to my invention, the shafts may be interconnectedby spur gears 21 of equal diameter, as indicated -in Fig. 3.

In 'the machine illustrated in Figs. 1 to 3, 'means is provided forregulating the rate at which aggregate is fed from the hopper 'i12 'intothe mixing compartment. vSuch means desirably comprises a 'plurality ofgates 319 mounted at the rear of the hopper l2 vfor sliding movementtoward and away 'from the feeder vl'l 'tolim'it the height of theopening through which aggregate leaves the hopper. As shown vin Fig. 4,two of the gates 'are employed, but itis to 'be Vunderstood that thenumber 'of -gates may be varied as desired. Whatever the number of gates-embodied in the machine, `each is yarranged for independent adjustment.As shown, each of the gates is provided with a pair of spaced racks 3lvcooperating respectively with fpinions v32 xed on a shaft 33 which 'canbe manually rotated 'to .ad- 'just 'the gate. -By rotating veither shaft33, its associated gate can be adjusted independently of the other gate.

Incorporated in the 'machine shown in the drawing is a means 'for'discharging ya binder upon the aggregate as it enters the :mixingcompartment. Conveniently, thism'eans 'takes the form of a plurality ofspray bars 235, 4one for each of the gates 39, arranged respectively inrear of such gates. Each 'spray .bar is provided with a series ofdischarge nozzles 35 'extending -into the mixing compartment l'81an'dindividually controllable by valves 3l'. is connected through ea supplypipe 38 with -a pump 39 (Fig. l) suitably mounted on the :frame of thevehicle.

Discharge Aof mixed 'material from `the mixing compartment t8 .iscontrolled by 'swinging -gate means `lll connected through links 1327with adjusting levers 43 pivotally supported .from the frame 'of thevehicle tand adjustable to vary the eifec'tive height fof 'the discharge"opening through which the mixed material escapes 'from'the mixingcompartment l'.

LSupported for vertical 'adjustment from lthe frame of the vehicleinrear'o the discharge'eom'- partrnent i8 :is va .distributing blade 45.'Conveniently, `vertical va'djustineni'. fof the 'blade :'45 Lis.secured 'through the :medium .of two .laterally :spaced adjustingscrews 56 which are rotatably `mounted lin the frame of the vehicle 'and'which Iare received'in nuts'attached to the blade #5. By vappropriateadjustment yof -the 'screws 4-6 the blade 45 may be placed at anydesired elevation above and at any-desired .inclination .to the roadsurface. If desired, there may be :mounted in advance `of .the xblade-45 .a `distributing :screw `48 adapted to feed material loutwardly -ofthe -ve- Each o'f 'the spray bars v35 1.

4 hicle. To confine material discharged from the mixing compartment l 8,the end walls I 9 of such compartment may extend rearwardly to a pointadjacent the distributing blade 45.

Power for operating the various parts of the machine may be derived froman engine 59 mounted in any convenient manner on the vehicle frame. Asshown, .the engine 59 drives two countershafts 5T and 52, one located infront of the engine and the other in rear thereof. The feed screw i4associated with the hopper l2 and the feeders Il are desirably drivendirectly from the countershaft 5|, as through chain drives 53 and 54respectively. One of the shafts 25 of the mixing element is' operativelyconnected to the .rear countersh'aft 52, as through the medium of achain drive 55, while a second chain drive 51 interconnects thecountershaft 52 with the distributor screw 48. Idlers 58 and 59,respectively 4associated with the chains E59 and 5l, may be employed tomaintain such chains at the desired tightness.

'The two pumps 39 are `conveniently driven from the Acountersh'aft .52through chain drives 5l. jD'esirabiy, for reasons that will hereinafterbecome apparent, the drive to each of the pumps 39 is individuallycontrolled lso that either or both ypinilps can be operated, lasdesired. As shown, earch of the chain drives 6| has associated with it amanually controllable iclutch B2 which can be operated alternativelyeither to connect the 'drive to lor disconnect it .from the countershaft252. .Bin-der may be supplied independently to the two pumps k3d in anyyconvenient manner, as through a supply "tank mounted -on .the vehicleitself or from 'a supply tank carredon a separate vehicle adapted tooperate beside the paving machine.

1n the operation of the machine illustrated in Figs. l to 4, thebin 2l 2is lledwith aggregate and the gates '39 and binder-discharge controlvalves 3l are :adjusted Eto provide tor the supply of aggregate and'binder at the desired rates. With the 'engine 50in operation `anddriving the mixing r'element-s Aand rthe binder-.supply pum-ps 3-9, thevehicle is drawn over the surface to be paved. As previously indicated,:the paving machine may v'be drawn by 4a dump `truck ib-ywhich thesupply of 'aggregate in the -bi-n t2 .may be continuously replenished.Fed V:from the bin +2 by the vfeeder VVIfl the 'aggregate receives asupply of 'binder discharged from the nozzles 36 asitentersthe mixingcompartment I8. Because the Abinder is distributed yover substantiallythe entire length of .the mixing compartment, much of the coatingoperation 4`will beperformed lwhen the binder-jets Afrom the nozzles .36fimping-e Vupon the aggregate. rCoa'ling of .the :aggregate .particlesis :promptly 'completed by y'operation of the rapidly rotating ixingelements. 'I he .action -of these elements .in 4throwing the aggregateviolently against the lupper wall 29 fof the mixing compartment breaks@up :any agglom'erated lumps of aggregate to ex- Ipose theenti-refsurfaoe of all theragglegate Dal- -ticles tothe binder.ilheainountof material in 'the mixing conipa-iitmerit is `vcontrolled by.adjustment fof ithegate 4l. .Escaping past the gate M, ythe material:rests on fthe #road surface and is ,leveled by `the action of Athe-`distributor blade 45 aided by thedistributorscrew 48, when suchdistributor .screw is used.

=It is 'to be noted .that zthe movement of aggregate particles Ifrom`the bin 'ft2 through the feeder aandfmixing compartmentisfgenerallylongitudinal of the vehicle, .AS .a result, `thegates 130,which control the discharge of aggregate from the bin I2, may beadjusted to vary the discharge of the mixed paving composition laterallyof the machine as it is discharged from the mixing compartment. Forexample, assuming that it is desired to lay aslab which is materiallythicker near its left-hand edge than near its right-hand edge, theleft-hand gate 30 may be opened wider than the right-hand gate to causeaggregate to be fed more rapidly from the left-hand end of the bin I2than from the right-hand end, and the valves 31 associated with thenozzles 36 in rear of the left-hand gate may be opened further than arethe valves 31 associated ,with the nozzles in rear of the right-handgate 30, to maintainsubstantially the same aggregate-binder ratio atboth sides of the machine. With the gates and nozzles so adjusted, thepaving composition discharged from the mixing compartment I8 will have asubstantially uniform composition, but much more of the material will bedischarged at the left-hand side of the machine than at the right-handside. The leveling blade 45 will of course be set with its left-handendhigher than its right-hand end, to produce `the slab of the desiredgraduated thickness. However, because the material as discharged fromthe mixer already is distributed approximately in the desired graduatedthickness, the distributor blade has little to do by way of causing thepaving material to move laterally. If desired, the ends of thedistributor 48 may be made independently vertically adjustable byadjusting mechanisms 63.

It will be understood, of course, that the speed of the mixing machineover the surface to be paved will be proportioned to the rate at whichthe paving composition is discharged from the mixing compartment I8.Where the vehicle which draws the paving machine is incapable ofoperating at a speed suiiiciently low to prevent the exhaustion of mixedpaving composition from the space ahead of the blade, such vehicle maybe stopped periodically while a supply of paving composition ispermitted to accumulate ahead of the distributor blade and between thewalls I9.

The divider I5, with which the bin I2 is shown as provided, is intendedprimarily to prevent the escape or" aggregate from the bin when thefeeder embodies two spaced belts I1. belt is used extending throughoutthe width of the bin, or if some other type of feeder free from gaps orinterruptions is employed, the divider I5 may be omitted.

Independent control of the gates 30 and of the pumps 39 permits themachine to be operated to lay a relatively narrow slab of pavingmaterial. Independent control of the binder nozzles 35 permits thepaving material produced in the machine to have a varying composition.For example, the respective quantities of binder discharged from theseveral nozzles 36 may be varied to take account of the eiTect of anybinder previously applied to the sub-grade upon which the pavement is tobe laid.

In the modincation of the invention illustrated in Fig. 5, an auxiliaryhopper'10 is mounted on the frame of the machine in rear of the mainhopper I2, such hopper being provided with its own feeder 1I discharginginto the mixing compartment I8 and with its own series ofdischargecontrol gates 12. An auxiliary set of spray bars 13, having itsown discharge nozzles 14 and nozzle-controlling valves 15, is alsoemployed to supply liquid to the paving composition.

If a single feeder The machine illustrated in Fig..5 is extremelyilexible, as it permits the incorporation of additional ingredients,liquid orl solid, in the mix and also permits such additionalingredients to be distributed in any desired manner transversely of theslab which the machine produces. For example, the bin 10 may be suppliedwith Portland cement and the spray bars' 13 with water. By dischargingaggregate from the bin I 2 and cement from the bin I0 into the mixingcompartment for the full lateral extent thereof, a concrete slab ofpaving may be produced. If desired, one of the valves 31, or a pluralityof successive valves 31, may be opened to supply a bituminous'binder.Binder so suppliedthrough nozzles 36 will not be distributed laterallyof the vehicle but will remain more or less confined in a narrow portionof the slab. By incorporating bituminous binder in a portion of theslab, the machine will produce a slab of pavement in which expansionjoints are incorporated after the manner vof my copending applicationSerial No. 573,938, filed January 22, 1945, now Patent No. 2,524,395.

An alternative method of operating the machine shown in Fig. 5 may beemployed in producing a concrete edge or shoulder for a bituminous slabof paving material. To effect this result, gates 12 and water-supplyvalves 15 are closed over that portion of the machine in which abituminous slab is to be formed, while the gates 'i2 and valves 13 areopened and the valves 31 closed over the remaining portion of the slab.A concrete mix, comprising aggregate, Portland cement, and water, willthen be discharged from the mixing compartment through onel portion ofthe lateral extent thereof, while a bituminous composition will bedischarged throughout the remaining lateral extent of thev mixingcompartment. The two different characters of mixes will not be separatedby a sharp line of demarcation, of course; but instead there will be aregion in which the paving composition will include both Portland cementand bituminous binder, `with the proportion of cement decreasing and theproportion of binder increasing ,in one direction laterally of the slab.The absence of any sharp line of demarcation separating the cement-boundaggregate from the bituminous-bound aggregate tends to prevent theoccurrence of cracks in the finished slab.

It will be understood, of course. that the distributor screw I8 will notlbe employed when the slabof paving material to be produced varies lncomposition.

Because of the very rapid mixing produced by the longitudinal rotatingmixing elements and because, by appropriate adjustment of the gates andnozzles, the necessity for lateral movement of paving material by thedistributor blade may be eliminated, only a very short time need elapsebetween the application of the binder or other liquid constitutes andthe completion of the slab. In fact, no difficulty is encountered incompleting the distribution of the paving composition by the distributorblade within two minutes or less of the time at which the binder firstcomes into contact with the aggregate. As a result, it is possible toincorporate in the bituminous binder or in the aggregate material suchas hydrated lime, or metallic salts such as aluminum sulfate, which willresult in a very quick setting of the paving material. The same factorswhich contribute to the rapid mixing and laying of the paving materialalso contribute to an efcient use E claim as; my invention;

1. Inf a paving' machine, a vehicle adapted to traverse. a surface' tobe paved, an aggregate bin extending transversely of the vehicle, amixing compartment extendingtransverselyl of the vehicle forsubstantially the full width of the pavement to be. laid, a mixingelement located in said mixingv compartment and rotatable on atransverse axis extending transversely of the vehicle, said compartmenthaving, a top Wall disposed above said mixing element and at its rear adischarge opening extending transversely of the vehicle, said mixinglelement having a plurality ofv teeth. distributed axially of theelement to engage and lift material in the mixing compartment withouteffectingany substantial displacement of" such. material axially of theelement, means for feeding aggregate from said bin simultan'eousiyy topoi-nts distributed along the extent of said mixing compartment, meansfor driving said mixing element at, a speed great enough to cau-se itto: tlirovvv material in` said compartment against' said top wall and ina direction such that said teeth move rearwardly' in the upper portionof their rotation, adjustable means to vary the relative quantities ofaggregate simultaneously fed by said feeding means to selected pointsdis,- tributed along the transverse extent ofthe mixing compartment, andmeans. for supplying a liquid binder at a predetermined rate toaggregate as it enters said mixing compartment and for regulating the.distribution of said binder throughout' the transverse extent of themixing compartment. l

' 2'. The invention set. forth in claim 1 with the 1 addition of a.leveling blade adjustably supported from. the vehicle in position tolevel material. discharged from said discharge opening.

3. The invention set forth in claim 1, with the addition that saidbinder-supply means comprises a plurality of spray bars arranged todischarge on different portions of the aggregate entering the mixingcompartment, and means for independentlysupplying binder to said spraybars.

4. The invention set forth in claim l, with the addition that saidbinder-supply means comprises a series of discharge nozzles extendingtransversely of the vehicle, and means for independently controlling thebinder-discharge from each nozzle.

5. The invention set forth 'in claim 1, with the addition that saidmeans forv regulating the rate of aggregate feed comprises a pluralityAof gates distributed along said aggregatev bin, each oi said gates.being independently adjustable.

6., The invention set forth in claim 1 with the addition thatsaidvcompartment has a bottom, aggregate-supportingwall closely adjacentwhich thev tips of` said teeth pass in the rotation of said mixingelements.

7. In a paving machine, a vehicle adapted to traverse a surface tobepaved, a mixing compartment extending transversely of the vehicle,v saidmixing compartment having inlet and discharge openings extending alongand generally co-extensive With its front and rear sides, feeding meansfor supplying aggregate to said compartment through and simultaneouslythroughout substantially the entire extent of said inlet opening and forvarying the relative quantity of aggregate fed by said feeding means toselected points distributed along the transverse extent of the mixingcompartment, means for supplying a liquid binder to said compartment andfor varying the distribution of such binder aloner the compartment, amixing element disposed in said compartment and rotatable about an axisextending transversely of the vehicle and provided withaggregate-engaging teeth to move the particles of aggregate inl planesextending longitudinally of the vehicle and Without substantialdisplacement of such particles laterally of the vehicle, and means forrotating said mixing elements in such direction that its upperportionmoves generally rearwardly during rotation.

8. The invention set forth in claim 7 With the addition that saidcompartment has a bottom, aggregate-supporting wall closely adjacentwhich the. tips of said teeth pass in the rotation of said mixingelements.

. KENNETH E'. McCGNNAUGl-IAY.

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